Gage with variable response amplifier

ABSTRACT

An improved gage in combination with an amplifier which will respond more rapidly to a change of signal in one direction than to a change of signal in the opposite direction and where the ratio of the response rate in one direction to the response rate in the other direction is adjustable.

United States Patent Edward Peonski West Dundee, Ill.

American Gage & Machinery Company GAGE WITH VARIABLE RESPONSE AMPLIFIER8 Claims, 4 Drawing Figs.

US. Cl.

1m.Cl G01b 5/00,

Field of Search 4/ 103, 103 (P); 33/143 (L), 147 (L), 147 (N), 174 (L),178 (E), 172 (E) [56] References Cited UNITED STATES PATENTS 2,708,7365/1955 Creveling et a1 324/103 2,997,651 8/1961 Richeson, Jr. et a1324/103 3,458,812 7/1969 Krussmann et a1. 324/ 103X PrimaryExaminer-Rudolph V. Rollinec Assistant Examiner-Ernest F. KarlsenAttorney-Gary, Parker, J uettner, Pigott and Cullinan ABSTRACT: Animproved gage in combination with an amplifier which will respond morerapidly to a change of signal in one direction than to a change ofsignal in the opposite direction and where the ratio of the responserate in one direction to the response rate in the other direction isadjustable.

I i If m 14a 13 l Z44 l i I z 1 oe eoepqw PATENTEU HAYES l97l swan 2 0r3 'PATENTEU m5 um SHEET 3 OF 3 fiaentona J FM 3 @215 ll GAGE WITHVARIABLE RESPONSE AMPLIFIER BRIEF SUMMARY OF THE INVENTION It is knownin the art to measure the thickness or other dimensions of a part byusing a gage head in combination with a comparator amplifier in such amanner that a movable element of the gage head is positioned inaccordance with the dimension of the part to be checked and a reading isproduced on the associated amplifier which reading is determined inaccordance with the position of the movable gage element.

For example, it is known in such a gage system to use a linear variabledifferential transformer where the coupling between the primary andsecondary windings of the transformer can be changed by varying theposition of an iron-alloy core that magnetically links the primary andsecondary windings. The movement of the core will then produce an outputat the secondary which varies with the position of the core. The coremay be mounted through linkages to a gage tip or other mechanicalsensing member that travels over the work. In this manner, the gage headmay be used to produce a DC voltage which is proportional to the lineardisplacement of the core and thus proportional to the dimension of thework, and such voltage may be applied to a DC meter which is properlycalibrated to indicate the dimension of the part.

One significant limitation with a known gage system of the foregoingtype is that the device is sensitive to any changes in the position ofthe gage tip and is incapable of evaluating whether or not such aposition change has been caused by a true change in the dimension of thepart or whether it has been caused by other factors. By way of example,where a gage is utilized to measure the thickness of moving metal sheetstock, and where the gage head includes a movable element the positionof which is controlled by the spacing between a pair of rollers whichengage against opposite sides of the sheet stock, false high readings ofthickness will often be produced due to bouncing or weaving of the sheetstock. Similarly, any substantial vibration of the sheet stock willproduce false high readings of thickness of the DC meter which isconnected to the gage head. Another frequent cause of false highreadings is due to dirt or contamination on the material being gaged,inasmuch as known gage devices are generally incapable of distinguishingbetween a true increase in the dimension of the work and an apparentincrease in such dimension caused by contamination of the work.

Certain known gage devices have been designed so as to produce anaverage reading based on the high and low dimensions which are sensed bythe gaging device. However, while such a device will in effect produce arelatively steady reading by averaging out the highs and lows, yet theresultant average reading which is produced is significantly influencedby the factors discussed above such as bounce, weaving, vibration andcontamination of the work, and thus such readings are stillsignificantly inaccurate for the reason that they are affected byfactors other than the true dimension of the work.

It is a general object of the present invention to provide an improvedgaging device which avoids the foregoing problems and provides accuratereadings of the dimension of the work by in effect ignoring falsereadings caused by factors other than a change in the true dimension ofthe work.

A more specific object of my invention is to provide a gage deviceincluding a gage head in combination with a variable response amplifierwhich affords a relatively rapid response to a signal change in onedirection and a relatively slow response to a signal change in theopposite direction, whereby apparent changes in the dimension of a partin a selected direction such as an apparent increase in the dimension ofa pan will be ignored unless the increase occurs gradually or ismaintained over a period of time so as to indicate an actual change inthe true dimension of the work in accordance with a change in theprocess of producing the same.

A further one of my objects is to provide a gage device as last abovementioned which includes means for varying the ratio of the responserate in one direction to the response rate in the other direction forpurposes of adjusting such ratio in accordance with the rate ofdimensional change of the work in a given manufacturing process.

- The foregoing and other objects and advantages of the invention willbe apparent from the following description of a preferred embodimentthereof, taken in conjunction with the accompanying drawings.

DESCRIPTION or THE DRAWINGS FIG. 1 is a perspective view of a stock gagefixture for use in gaging the thickness of sheet stock, such fixturebeing one example of the manner in which a gage device may be used incombination with a variable response amplifier in accordance with thepresent invention;

FIG. 2 is an enlarged fragmentary front elevational view of the stockgage fixture of FIG. 1 showing in particular a gage head for connectionwith a variable response amplifier in accordance with the presentinvention;

FIG. 3 is a block diagram showing a delay circuit in accordance with thepresent invention added to a conventional amplifier circuit; and

FIG. 4 is a schematic wiring diagram showing the delay circuit of FIG.3.

Now, in order to acquaint those skilled in the art with the manner ofmaking and using my invention, I shall describe, in conjunction with theaccompanying drawings, a preferred embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings,FIG. 1 shows a strip stock gage fixture 10 comprising a pair of sideframe walls 12 and 14 interconnected by horizontal beam members 16 and18. An upper shaft 20 extends horizontally between the sidewalls 12 and14 and has its ends joumaled in bearings mounted in the sidewalls suchas shown at 22 so as to be rotatable about its longitudinal axis. Acentral support bracket 24 is bolted to the horizontal beam 16 andincludes a lug 26 which is apertured so as to permit the rod 20 to passtherethrough/A roller support bracket 28 is fixedly mounted on the shaft20 for rotation therewith, and the bracket 28 carries at its lower end arotatable crowned roller 30 for engagement with the upper surface of amoving strip of sheetstock S, as will be described more fully laterherein. There is also provided a lower shaft 32 which extendshorizontally between the sidewalls 12 and 14 and has its ends journaledin bearings mounted in the sidewalls such as shown at 34. A rollersupport bracket 36 is fixedly mounted on the shaft 32 for rotationtherewith, and the bracket 36 carries at its upper end a rotatablecrowned roller 38 for engagement with the underside of the moving stripof sheet stock S. I

It will be understood from the foregoing that the sheet stock S passesbetween the rollers '30 and 38, and the rollers bear against the upperand lower surfaces of the sheet stock in such a manner that thethickness of the sheet stock S determines the spacing between therollers. The lower roller support bracket 36 has a small block 40secured thereto, and a threaded rod 42 is rigidly affixed to the block40 and extends downwardly therefrom so as to project through an aperturein a horizontal flange 44 which forms an integral part of a slidebracket 46. The block 40 is pivotally mounted relative to the rollersupport bracket 36 so as to permit pivotal movement of the rod 42relative thereto.

The slide bracket 46 is vertically adjustable in relation to a mountingplate 48 which is fixedly mounted to the horizontal crossbeam 18. Themounting plate 48 has fixedly secured thereto a block 50 through which athreaded adjusting screw 52 projects. The screw 52 is disposedvertically and its upper end is threaded through a block or nut 54 whichis affixed to the vertically adjustable slide bracket 46. The slidebracket 46 is connected to the fixed mounting plate 48 by means of apair of bolts 56 and 58 which extend through corresponding verticalslots in the slide bracket 46 so as to permit vertical adjustment of thelatter.

It will be understood from the foregoing that rotation of the screw 52will afford adjustment of the vertical position of the bracket 46. Itwill also be noted that a compression spring 60 is mounted on thevertical rod 42 so as to extend between the block 40 and the horizontalflange 44. A nut 62 is threaded on the lower end of the rod 42 beneaththe flange 44, and it will be seen that through advancement of the nut62 on the rod 42 the latter will be drawn downwardly thereby causing theroller support bracket 36 to be pulled downwardly in a pivotal motionabout the axis of the shaft 32.

The foregoing downward adjustment of the roller 38 will further compressthe spring 60 which biases the roller support bracket 36 upwardly to alimiting position as determined by the rod 42 and nut 62. It willtherefore be seen that the crowned roller 38 is generally disposedapproximately at the upper limit of its travel and that it is capable ofdownward movement in a pivotal manner about the axis of the shaft 32 ifa force is applied thereto sufficient to compress the spring 60. Theforce of the spring 60 as well as the position of the roller 38 isadjustable by means of the nut 62, whereas adjustment only of theposition of the roller 38 may be effected through rotation of the screw52.

The upper crowned roller 30 is biased downwardly toward the lower roller38 by means of an air cylinder 64, the lower end of which is connectedto the side frame wall 12 and the upper end of which is connected to acrank arm 66 which is fixedly mounted on the upper shaft for rotationtherewith. Accordingly, air is supplied to the cylinder 64 so as to urgethe piston rod 68 downwardly thereby biasing the roller in a downwarddirection while permitting the same to be displaced upwardly if arelatively small force is applied thereto.

As explained hereinabove, the foregoing arrangement provides forengagement of the crowned rollers 30 and 38 against the oppositesurfaces of sheet stock S which is passed therebetween, and the spacingof the rollers from one another is thus determined by the thickness ofthe sheet stock. Still referring to FIG. 1, it will be seen that an arm70 is mounted at the extreme right-hand end of the upper shaft 20 forrotation therewith. The arm 70 carries a swivel block 72 which in turncarries a cylindrical member 74 on which is mounted a micrometer anvil76. The cylindrical member 74 is disposed intermediate a pair of flanges78 and 80 formed on the arm 70. In a similar manner, an arm 82 ismounted at the extreme right-hand end of the lower shaft 32 for rotationtherewith. The arm 82 carries a swivel block 84 which in turn carries acylindrical member 86 in which is mounted a gage head 88, the latterbeing disposed between a pair of flanges 90 and 92 formed on the arm 82.

It will now be understood with reference to FIGS. 1 and 2 that thespacing between the crowned rollers 30 and 38 will control the spacingbetween the micrometer anvil 76 carried by the arm 70 and the gage head88 carried by the arm 82. In the particular embodiment being described,the anvil 76 comprises a conventional micrometer having an anvil member94 at its lower end (see FIG. 2) which is vertically adjustable throughrotation of the knurled knob 96 at the upper end thereof. As shown inFIG. 2, the gagehead 88 comprises a conventional gage head having aplunger 98 at its upper end which projects out of a housing 100 and isspring biased upwardly into engagement with the lower end of the anvil94. Accordingly, the amount by which the plunger 98 projects out of thegage head housing 100 depends upon the spacing of the crowned rollers 30and 38, which in turn is governed by the thickness of the sheet stock Sas it moves between the rollers.

As shown in FIG. 1, the gage head 88 is connected by means of a cable102 to an amplifier 104 including a meter 106, the reading on the meterbeing a measurement of the thickness of the sheet stock S. FIG. 3 showsa block diagram of the circuit for the amplifier 104, such circuit beingconventional except for the addition of a delay circuit in accordancewith the principles of the present invention.

As is known in the art, the gage head 88 includes a linear variabledifferential transformer as shown at 108 in PK). 3. The coupling betweena primary winding 110 and secondary windings 112 and 114 of thetransformer can be changed by varying the position of the iron-alloyplunger or core 98 which magnetically links the primary and secondarywindings. The movement of the core 98 produces an output at thesecondary which varies with the position of the core. The two secondarywindings 112 and 114 are wired in opposition to one another so that whenthe core 98 links both secondary coils 112 and 114 equally the voltageswill oppose each other and the gage head will produce a zero output.

Since the secondary coils 112 and 114 are wired in phase opposition, theoutput is either positive or negative when the core 98 is on either sideof the zero position. Thus, readings to the right or left of zero arepossible on the meter 106. Because the output of the transformer 108 issmall, an amplifier 116 is utilized to boost the signals to usefullevels. After the signal is amplified, phase detection is accomplishedwith a synchronous detector 118 and, in a conventional device, thesignal is then transmitted to a meter circuit 120. Excitation or drivingvoltage for the transformer 108 is provided by an oscillator 122 whichis connected to the primary winding 110, and a zero control circuit 124is provided so that zero DC voltage output can be set to correspond to agiven displacement reference position of the plunger 98.

It will be understood from the foregoing that the gage head 88 may bepositioned so that it follows the work to be gaged,

or it may be used in conjunction with other sensing members such as thecrowned rollers 30 and 38 of FIG. 1 which follow the work. In any suchapplication, whether or not the plunger 98 directly engages the work,the position of the plunger is a measure of the dimension of the work,and by means of the circuit shown in FIG. 3, the plunger position can bereflected on a meter such as shown at 106 in FIG. 1.

In accordance with one embodiment of the present invention a delaycircuit 126 is interposed in the amplifier circuit between thesynchronous detector 118 and the meter circuit as shown in FIG. 3. Itshould be recognized that without the delay circuit 126 the system shownin FIG. 1 will function in such a manner that the meter reading on themeter 106 will be responsive to any change in the spacing between thecrowned rollers 30 and 38, and that such response will be equally rapidregardless of the direction of the change, that is, regardless ofwhether the spacing of the rollers is increased or decreased. Thus,referring by way of example to a gage fixture for gaging sheet stock asshown in FIG. 1, various factors such as bouncing or weaving of thesheet S, vibration, and also the presence of dirt or contamination onthe sheet will temporarily affect the spacing of the rollers 30 and 38,and the device will be responsive thereto and will produce false highreadings of the thickness of the sheet S. Moreover, even if moresophisticated equipment were utilized to produce an average thicknessreading, the average reading would still be influenced by the variousfactors discussed above and thus would be inaccurate.

The delay circuit 126 which is added to the amplifier circuit of FIG. 3in accordance with the present invention affords an improved gage systemwhich eliminates the foregoing problems and inaccuracies. The delaycircuit is illustrated in FIG. 4 which shows a connector board 128having an input terminal indicated as 7 where the voltage signal isreceived from the conventional amplifier circuit, e.g., from thesynchronous detector 118 of FIG. 3, there being an input lead 130connected to the terminal 7. There is also shown an output terminalindicated at 3 where an output signal from the delay circuit 126 issupplied to the meter circuit as shown at 120 in FIG. 3. Additionalterminals 4" and 6 and the ground terminal 9" represent the voltagesupplies for the delay circuit.

Still referring to FIG. 4, the input voltage signal to the delay circuitis conducted over the lead 130 to an input filter 132 so that electricalnoise and the like will be suppressed. Thereafter, the DC signal issupplied over a lead 133 to an operational amplifier 134 which producessufficient amplification to provide the correct dynamic level of thefollowing circuitry. The DC signal is then transmitted over a lead 135to a diode 136 which in turn is connected over a lead 138 to a capacitor140 whereby the input signal serves to charge the capacitor. Thecapacitor 140 is connected by a lead-142 to a buffer amplifier 144 whichin turn is connected through a resistance 146 and a lead 148 to theoutput terminal indicated at 3." As previously explained, the outputterminal 3" leads to the meter circuit 120 of FIG. 3. Consequently, itwill be understood that the charge on the capacitor 140 produces areading on the DC readout meter, and that such reading will thereafterbe permitted to diminish at a rate which depends upon the rate ofdischarge of the capacitor 140.

In order to control the rate of discharge of the capacitor 140, there isconnected in the discharge path a variable resistor 150. Inasmuch as thediode 136 is in essence a unidirectional conductor, the rate ofdischarge of the capacitor 140 can be controlled by either varying thecapacitor itself or by varying the resistance 150, and in the embodimentbeing described such control is effected by varying the resistance 150.In other words, once a signal over the output lead 148 has produced areading on the meter 106, the rate at which such a reading can decay ordiminish is controlled by varying the resistor I50, and through suchadjustmentthe rate of decay may be severely limited. On the other hand,if a further input signal of greater magnitude is conducted through thediode 136 so as to increase the charge on the capacitor, the increasedinput signal will be conducted over lead 148 to the meter circuitwithout any appreciable delay.

It is important to understand from the foregoing that in accordance withthe present invention the response rate of the circuit may be controlledso that the gaging system will have a very rapid response for a changein the magnitude of the signal in one direction'and a relatively slowresponse to a change of the magnitude of signal in the oppositedirection. In other words, the system will provide a rapid response to asignal change in one direction, i.e., a signal of increased magnitude,but will provide a slower response to a signal change in the oppositedirection, i.e., a signal of lesser magnitude, the reason being that thesystem can only respond to a lesser signal in accordance with the rateof discharge of the capacitor 140. It is also important to understandthat the ratio of the two response rates can be varied substantially byvarying the foregoing discharge rate, as for example by varying theresistor 150. As an illustration, the delay circuit may be designed sothat the ratio is adjustable between I and 300, means that by adjustingthe decay rate to one extreme the two response rates maybe made equal,and by adjusting the system to the other extreme the rate of response toan increase in the magnitude of the signal may be made 300 times as fastas the rate of response to a decrease in the magnitude of the signal.

It should also be noted in connection with the present invention that,depending upon the application to which my improved gage system is put,it is a simple matter to alter the system so that it will have a rapidresponse in a preselected direction and a slow adjustable response inthe opposite direction. For example, in an application as described inconjunction with FIG. it will normally be desirable to connect the delaycircuit I26 so that the system will respond very rapidly to any decreasein the thickness of the sheet stock 5 but will respond at a slower rateto an apparent increase in such thickness.

On the other hand, in certain applications, as for example in connectionwith the grinding of external surfaces having gaps or interruptionstherein, it is necessary to utilize a gaging system which is capable ofignoring the surface interruptions. In an application of the lattertype, the system would be connected so as to afford a very rapidresponse to a reading which corresponds to a maximum dimension of thepart, i.e., a rapid response to any increase in the part size, while onthe other hand when a gap or interruption in the external surface of thepart produces a signal change in the opposite direction, it is desirableto afford a very slow response rate to the resultant signal change,thereby in effect ignoring such surface interrupit is significant tonote that by simply reversing the polarity of the voltage input to thedelay circuit 126, and at the same time reversing the readout meter-106,it is possible to reverse the gaging system and thereby preseleet thetype of signal change which is to receivev a fastv response and the typeof signal change which is to receive a slow response.

Referring again to the particular strip stock gage fixture shown in FIG.I, it will be assumed that the delay circuit l26'is connected so thatthe system'will respond very rapidly to any decrease in the thickness ofthe sheet stock S but will respond slowly toan apparent increase in thethickness of the sheet. Consequently, if due tobouncing or weaving orvibration of the sheet S, or due to contamination of the sheet, thespacing between the crowned rollers 30 and 38 is temporarily increased,even though the true thickness of the sheet has not increased, the gagesystem of the present invention will ignore such false high readings. Inother words, the meter 106 will not indicate such high readings but willcontinue to indicate what in effect is a reading of the minimumthickness of the part.

Thus, in the particular example described above, the gaging device ofthe present invention can be utilized to read the minimum thickness, ofa part while ignoring all false high readings which would be reflectedas an increasein thickness by a conventional gage system. On the other.hand, it will be understood that while the particular system beingdescribed in the foregoing example has a slow response rate to anapparent increase in the thickness of the sheet S, such slow responserate can be adjustedso that the system will respondto a true increase inthe thickness of the sheet. Such selectivity can be achieved for thereason that a true increase in the thickness of thesheet will occur in agradual manner or will be maintained over a period of time sufficient toallow the system to respond thereto. In otherwords, even the slowest ofthe two response rates of my gaging system must be as fast as any truechange in the dimension of the work caused by a change in the process ofproducing the same.

tions. Accordingly,

Referring again to FIGS. land 2, there is shown an alignment barl52. Thebar 152 is generally vertically disposed and its upper end projects intoan aperture formed in the swivel block 72, while-the lower end of thebar extends through an aperture formed in the swivel block- 84. Thealignment bar 152 is fixed relative to the swivel block 72 by means of asetscrew 154, whereas the bar is capable of sliding movement in thelower swivel block 84. The purpose of the alignment bar 152 incombination with the swivel blocks 72 and 84 is to maintain themicrometer anvil 76 in alignment with the gage head 88. Thus, in theparticular gage fixture shown in FIG. 1, a vertical displacement of thesheet, e.g., an upward movement thereof, will cause the roller .30 to bedisplaced upwardly, thereby producing a pivotal movement of the arm 70about the axis of the bar 20.

If the foregoing movement were substantial, the resulting pivotalmovement of the micrometer anvil 76 would produce a situation where themicrometer anvil 76 would no longer be coaxial with the gage head 88. Inaccordance with the present invention, the micrometeranvil 76 is capableof pivotal movement about a horizontal axis along with the swivel block72, while the gage head 88 is capable of pivotal movement about ahorizontal axis along with the swivel block 84. Consequently, regardlessof the positions to which the rollers 30 and 38 are moved, the alignmentbar 152 will maintain the micrometer anvil 76 in coaxial relation withthe gage head 88, thereby assuring proper contact between the anvil tip94 and the tip of the plunger 98.

FIG. 2 further shows a bar I56 which extends upwardly from the swivelblock '84, and a rod 158 which is threaded through the swivel block 72and projects downwardly therefrom. The bar I56 is'fixed relative to theblock 84, while the rod 158 may be vertically adjusted relative to theblock 72 and locked in a given position by means of a nut 160. The bar156 and rod 158 function as stop members so as to limit the amount bywhich the anvil member 94 can force the plunger 98 into the gage head88. In this manner, the gage head is protected against application ofexcessive force.

As has been explained hereinabove, the preferred embodiment of thepresent invention includes means for varying the ratio of the responserate to a signal change in one direction to the response rate to asignal change in the opposite direction, and in the particularembodiment described such means comprises the variable resistor 150. Theadvantage in being able to vary the ratio of the response rates is topermit adaption of the gage system for optimum use with variousmanufacturing processes. The desired ratio will vary depending upon therate of true dimensional change of the work likely to occur inaccordance with a particular manufacturing process.

In general, the rate of response in one direction will always be quiterapid, and in many applications it is not essential that this rate ofresponse be adjustable. The slower rate of response in the oppositedirection is adjustable and is preferably made as rapid as is possiblewithout introducing errors into the readings. Accordingly, when settingup my gage system for operation, an appropriate procedure is to beginwith a maximum response ratio setting, i.e., a rapid response in onedirection and a very slow response in the opposite direction, and thentest the operation of the gaging device by reducing the response ratiountil a point is reached where the readings indicate an improper shifttoward the plus side. In other words, assuming that the object is toread a minimum thickness of the work and to ignore false high readings,the response ratio is gradually reduced until there are indications thatimproper high readings are being produced, as for example bycontamination of the work or vibration thereof, at which point theresponse ratio is set high enough to eliminate all such false highreadings.

There are many applications for the present invention of the typedescribed hereinabove where the object is to read a minimum thickness orother dimension of the work and ignore higher readings unless the higherreadings occur gradually or are maintained over a period of timesufiicient to indicate that they are true dimensional changes in thework resulting from the manufacturing process and not from contaminationor from an inability to hold the work steady during the gaging thereof.However, there are other applications where as previously mentioned thegaging device may be connected so as to read a maximum dimension such asthe outer diameter of a part while ignoring lesser readings unless suchlesser readings occur gradually or are maintained for a time sufficientto indicate that they represent true dimensional changes in the work.

An example of an application of the latter type is in connection withthe grinding of external surfaces having interruptions or gaps therein,such as elliptical pistons, splined shafts, etc. In such cases, thepresent invention may be used to gage a maximum dimension such as theouter diameter of the part, while ignoring the gaps or interruptions,i.e., the readings on the readout meter will not reflect the gaps orinterruptions. Another example is where a plurality of parts in spacedrelation are fed seriatim past a gage, in which case a gage may be usedin accordance with the present invention which will in effect ignore thespaces between the parts.

The present invention may be used with various types of gage heads, andin fact may be used in conjunction with virtually any gaging systemwhich produces an electrical output signal. For example, it may be usednot only with gages having a plunger which contacts the work, or havinga plunger which is connected mechanically to a sensing member whichcontacts the work, but it may also be used with various types ofelectrical air gages including noncontact air gages.

The present invention permits the use of gaging techniques which wouldotherwise be impossible in many situations. For example, the strip stockgage fixture 10 shown in FIG. 1 would simply not be practical and wouldnot produce accurate results without the use of a delay circuit inaccordance with the present invention. In any such application where itis not possible to keep the work steady as it passes the gage, or in anysituation where it is not possible to avoid contamination of the workbeing gage, accurate results are possible only by virtue of theimprovements produced by the present invention. In other words, theconventional procedure for measuring the thickness of sheet stock suchas shown at S in FIG. 1 is to periodically stop the sheet and manuallyuse a micrometer to check the edge portions of the sheet.

Moreover, I have found that many existing gage systems can easily beconverted for operation in accordance with the present invention so asto produce greatly increased accuracy without the necessity ofcompletely rebuilding such systems. In other words, many such existinggage devices can be converted by simply modifying the amplifier circuitto add a delay feature in accordance with the principles of the presentinvention.

lclaim:

1. A gaging device for gaging a dimension of work to be checked whilethe latter is in motion, comprising, in combination, sensing means pastwhich the work is moved, electrical means responsive to said sensingmeans for producing an electrical signal which varies in accordance withthe dimension of the work as sensed by said sensing means, readout meansfor displaying a reading which is indicative of the dimension of thework, said readout means being controlled by said electrical means, andamplifier means interposed between said electrical means and saidreadout means for receiving electrical signals from said electricalmeans and controlling the input to said readout means, said amplifiermeans having two response rates to electrical signals supplied thereto,there being one response rate to a signal change which indicates anincrease in the dimension of the work and a second response rate to asignal change which indicates a decrease in the dimension of the work,said two response rates being substantially difierent from one another.

2. The device of claim 1 including means for varying at least one of thetwo response rates.

3. The device of claim 1 where the response rate to a signal changewhich indicates an increase in the dimension of the work is very slow incomparison to the response rate to a signal change which indicates adecrease in the dimension of the work whereby said device will tend toread a minimum dimension of the work while ignoring apparent increasesin such dimension unless the increase occurs gradually or is maintainedfor a time sufficient for the slowest of the two response rates torespond thereto.

4. The device of claim 1 where the response rate to a signal changewhich indicates a decrease in the dimension of the work is very slow incomparison to the response rate to a signal change which indicates anincrease in the dimension of the work whereby said device will tend toread a maximum dimension of the work while ignoring apparent decreasesin such dimension unless the decrease occurs gradually or is maintainedfor a time sufficient for the slowest of the two response rates torespond thereto.

5. The device of claim 2 where said means for varying at least one ofthe two response rates pennits adjustment of the ratio of the fasterresponse rate to the slower response rate to a ratio factor of at leastto l.

6. The device of claim 1 where said amplifier means includes a readoutmeter and where an electrical delay circuit is interposed prior to saidreadout meter for delaying a change in the meter reading in onedirection while permitting a substantially more rapid change in themeter reading in the opposite direction.

7. The device of claim 6 where said delay circuit includes capacitormeans which is charged when a signal is supplied to said meter and whichis connected with said meter to temporarily delay change in a meterreading in one direction while permitting a more rapid change in theopposite direction, and means for adjusting the rate of discharge ofsaid capacitor means in order to control the magnitude of said delay andthereby control the rate of response of said device to a signal changein said one direction.

8. The device of claim 7 including variable resistor means forcontrolling the rate of discharge of said capacitor means.

1. A gaging device for gaging a dimension of work to be checked whilethe latter is in motion, comprising, in combination, sensing means pastwhich the work is moved, electrical means responsive to said sensingmeans for producing an electrical signal which varies in accordance withthe dimension of the work as sensed by Said sensing means, readout meansfor displaying a reading which is indicative of the dimension of thework, said readout means being controlled by said electrical means, andamplifier means interposed between said electrical means and saidreadout means for receiving electrical signals from said electricalmeans and controlling the input to said readout means, said amplifiermeans having two response rates to electrical signals supplied thereto,there being one response rate to a signal change which indicates anincrease in the dimension of the work and a second response rate to asignal change which indicates a decrease in the dimension of the work,said two response rates being substantially different from one another.2. The device of claim 1 including means for varying at least one of thetwo response rates.
 3. The device of claim 1 where the response rate toa signal change which indicates an increase in the dimension of the workis very slow in comparison to the response rate to a signal change whichindicates a decrease in the dimension of the work whereby said devicewill tend to read a minimum dimension of the work while ignoringapparent increases in such dimension unless the increase occursgradually or is maintained for a time sufficient for the slowest of thetwo response rates to respond thereto.
 4. The device of claim 1 wherethe response rate to a signal change which indicates a decrease in thedimension of the work is very slow in comparison to the response rate toa signal change which indicates an increase in the dimension of the workwhereby said device will tend to read a maximum dimension of the workwhile ignoring apparent decreases in such dimension unless the decreaseoccurs gradually or is maintained for a time sufficient for the slowestof the two response rates to respond thereto.
 5. The device of claim 2where said means for varying at least one of the two response ratespermits adjustment of the ratio of the faster response rate to theslower response rate to a ratio factor of at least 100 to
 1. 6. Thedevice of claim 1 where said amplifier means includes a readout meterand where an electrical delay circuit is interposed prior to saidreadout meter for delaying a change in the meter reading in onedirection while permitting a substantially more rapid change in themeter reading in the opposite direction.
 7. The device of claim 6 wheresaid delay circuit includes capacitor means which is charged when asignal is supplied to said meter and which is connected with said meterto temporarily delay change in a meter reading in one direction whilepermitting a more rapid change in the opposite direction, and means foradjusting the rate of discharge of said capacitor means in order tocontrol the magnitude of said delay and thereby control the rate ofresponse of said device to a signal change in said one direction.
 8. Thedevice of claim 7 including variable resistor means for controlling therate of discharge of said capacitor means.